This specification relates to detecting sources of computer network failures.
A typical computer network includes multiple computers connected together through one or more links and one or more network devices, e.g., switches or routers. Computer networks can experience partial or total failure for many reasons, including the failure of one or more components of the computer network. For example, the failure of some links in a computer network can cause problems in transmitting certain network flows. The diagnostic logic of network devices in the network may fail to detect such link failures, which in turn can cause a situation where the computer network continues to use failed links for packet forwarding. Detecting sources of computer network failures may be difficult because it may not be practicable or feasible to investigate every component of a computer network. This is especially the case for larger networks with numerous hosts, links, and switches.